Robust State Sharing for Wide Area Distributed Applications

Abstract

In this article, we present the Mocha wide area computing infrastructure we are currently developing. Mocha provides support for robust shared objects on heterogeneous platforms, and utilizes advanced distributed shared memory techniques for maintaining consistency of shared objects that are replicated at multiple nodes to improve performance. In addition, our system handles failures that we feel will be common in wide area environments. For example, to ensure that the state of an object is not lost due to a node failure, updated state of the object can be disseminated to several other nodes. The overhead of such state dissemination can be controlled based on the level of availability needed for shared objects. We have used an approach that makes use of multiple communication protocols to improve the efficiency of shared object state transfers in Mocha. We also provide an empirical evaluation of our prototype implementation for both local and wide area networks and present a sample home service application written with the system.